Method for pest control

ABSTRACT

The present invention relates to the technical field of controlling harmful organisms in the cultivation of cultivated plants. The present invention relates to a method for controlling harmful organisms, to a system for controlling harmful organisms and to the use of a digital application map for the application of one or more control agents against harmful organisms.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/311,191, filed on Dec. 19, 2018, which is a national stage entryunder 35 U.S.C. § 371 of International Application No.PCT/EP2017/065536, filed on Jun. 23, 2017, which claims the benefit ofpriority of European Patent Application No. 16185502.8, filed on Aug.24, 2016, and European Patent Application No. 16176650.6, filed on Jun.28, 2016, the disclosures of which are hereby incorporated by referenceherein in their entireties.

TECHNICAL FIELD

The present invention relates to the technical field of controllingharmful organisms in the cultivation of cultivated plants. The presentinvention relates to a method for controlling harmful organisms, to asystem for controlling harmful organisms and to the use of a digitalapplication map for the application of one or more control agentsagainst harmful organisms.

BACKGROUND

During the cultivation of cultivated plants, there are many differentorganisms which can reduce the yield, can adversely affect the qualityof the harvest or can exert some other undesired effect on thecultivated plants or the harvested crop.

Such harmful organisms are, for example, weeds and grass weeds, fungi,animal pests and pathogens

In addition, there are many different measures and means for preventing,reducing or controlling such harmful organisms

By using herbicides, for example, it is possible to successfully controlweeds and grass weeds during the cultivation of cultivated plants.

However, resistances are increasingly observed during the use ofherbicides. The development of a resistance to a herbicide is a naturalprocess which makes it possible for plants to adapt themselves to theirenvironmental conditions and to thus ensure their survival

The development of resistant plants starts with single individuals whichoccur naturally in each population, and which are resistant to theagents used.

Repeated uses of herbicides having the same or similar mechanisms ofaction lead to a selection pressure on the weeds. Said selectionpressure favours the survival of accordingly adapted (resistant)individuals. If no strategy to avert or interrupt this selection processis carried out, resistant individuals can become prevalent over timewithin a population. This gives rise to the initial control problems andthere is eventually a resistant population.

This applies not only to the control of weeds and grass weeds withherbicides, but also analogously to the control of other harmfulorganisms with appropriate control agents.

To prevent the formation of a resistance, what must be done is to usecontrol agents against the harmful organisms only where it is necessaryand only to the extent that it is necessary.

In relation to the specific use of control agents, various approacheshave been published in the past years.

Published specification WO95/01719 describes a computer system by meansof which a field is first divided into multiple zones which areindependently monitored. An irrigation and the use of chemicals is theneffected zone by zone depending on the needs ascertained by themonitoring. The ongoing observation of the zones requires correspondingsensors and also means for data acquisition, data processing and dataanalysis.

U.S. Pat. No. 6,199,000 describes a method in which an RTK GPS (RealTime Kinematic Global Positioning System) receiver is used during theplanting of crop plants in order to generate a digital map of the field.Owing to the high accuracy of position determination by RTK GPS, thelocations of the individual crop plants are accurately registered on thedigital map down to a few centimetres. A vehicle equipped with anappropriate sensor (e.g. a “chlorophyll detector”) can thereforeidentify plants growing at sites at which no seeds have been introducedinto the soil. If plants are detected at spots at which no sowing hasbeen carried out, a weed is highly likely to be involved. This weed canthen be directly controlled on the spot.

WO00/23937 describes a computer system. Part of the computer system is adigital map of an agricultural field which is based on a photographicimage, and which contains geographical longitude and latitudeinformation, making a position determination possible. In said digitalmap, it is possible for a user to define zones. The user can assign tothe zones formulations of substances (fertilizers, pesticides,herbicides) and quantities of said substance formulations to be applied.The computer system can generate a data set. Said data set allows afarmer to approach the various zones of the agricultural land with theaid of a corresponding vehicle and to apply the corresponding quantitiesof corresponding formulations according to the assignments made.

The thesis by Carina Ritter (Evaluation ofweedpopulations under theinfluence of site-specific weed control to derive decision rules for asustainable weed management, Institute of Phytomedicine, Weed ScienceDepartment, University of Hohenheim, under the supervision of Prof. Dr.R. Gerhards, 2008) describes how a digital distribution map of weeds(Galium aparine L. and Alopecurus myosuriodes HUDS) was generated andherbicide was applied in a location-specific manner on the basis of saidmap with the aid of a DGPS-controlled (DGPS=Differential GlobalPositioning System) spraying device. This involved taking into accountweed thresholds to some extent. The digital weed distribution maps werefirst generated for each of multiple years and then a treatment withherbicides was performed on the basis of the maps, with a herbicideformulation being applied in a location-specific manner only once ineach year (see in particular Table 1 in section 2.2.2 and Table 6 insection 3.2.3). What was observed was that, in some fields, weed nestsappeared which survived for several years.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE shows different representations of a field at various pointsin time.

DESCRIPTION

Proceeding from the described prior art, a person skilled in the art isconfronted with the technical object of controlling harmful organismseffectively and efficiently, wherein the use of control agents is to belimited to a meaningful and economical extent, and the risk of theformation of resistances to the control agents used is to be reduced. Itis also necessary to prevent the formation of stable nests of harmfulorganisms.

This object is achieved by the subjects of the independent claims.Preferred embodiments can be found in the dependent claims and in thefollowing description.

The present invention firstly provides a method for controlling harmfulorganisms on a field on which cultivated plants are cultivated, whichmethod has the following steps: (A) generating a digitalharmful-organisms distribution map on which subareas on the field areregistered, in which subareas the harmful organisms have been detected;B) generating a digital application map on the basis of the digitalweeds distribution map, it being registered on the digital applicationmap those subareas of the field on which subareas one or more controlagents against the harmful organisms are to be applied, it beingregistered for each of said subareas a number N of treatments with oneor more control agents, where N is greater than 1; C) applying one ormore control agents against the harmful organisms as per the digitalapplication map from step (B), the number N for the treated subareasbeing reduced by 1 as a result of the treatment; D) repeating step (C)for each subarea until N has reached the value zero.

The present invention further provides a digital application map onwhich subareas of a field for cultivated plants are registered, whichsubareas are to be treated with one or more control agents againstharmful organisms, wherein for each of these subareas an integer N isregistered, which specifies how many times the subarea is to be treatedwith one or more control agents for the harmful organisms, where N isgreater than 1.

The present invention further provides a system for controlling harmfulorganisms, comprising: a) a digital application map on which thosesubareas of a field which are to be treated with one or more controlagents for the harmful organisms are registered;

(b) a position determination system; (c) an application devicecomprising

at least one container for accommodating at least one control agentagainst the harmful organisms,

a spray device for applying the at least one control agent, and

a control unit comprising a memory for reading in the digitalapplication map, means for communicating with the position determinationsystem and means for controlling the spray device,

wherein a number N is registered on the digital application map for eachsubarea, which number specifies how many times a treatment of thesubarea with the control agent is to take place, where N is greater than1, and where the control unit is equipped in such a way that the numberN is reduced by one after a treatment has taken place.

The present invention further provides for the use of a digitalapplication map on which subareas of a field for cultivated plants areregistered, in which subareas a treatment with one or more controlagents against harmful organisms is to take place, for the applicationof one or more control agents against the harmful organisms, wherein anumber N is registered on the digital application map for each of thesubareas, which number specifies how many times a treatment of thesubarea with one or more control agents is to take place, where N isgreater than 1, and where the number N is reduced by one after atreatment of the subarea has taken place.

The invention will be more particularly elucidated below withoutdistinguishing between the subjects of the invention (method,application map, system, use). On the contrary, the elucidations beloware intended to similarly apply to all subjects of the invention,independent of in which context (method, application map, system, use)they occur.

Hereinafter, a “harmful organism” is understood to mean an organismwhich can appear during the cultivation of cultivated plants and damagethe cultivated plant, adversely affect the harvest of the cultivatedplant or compete with the cultivated plant for natural resources.Examples of such harmful organisms are weeds, grass weeds, animal pestssuch as beetles, caterpillars and worms for example, fungi and pathogens(e.g. bacteria and viruses). Even though viruses are not counted amongstorganisms from a biological point of view, they are nevertheless to becovered here by the term harmful organism.

In the literature, there are sometimes overlaps amongst the statedharmful organisms. Especially in the case of fungal attack, fungus anddisease are often discussed synonymously. A further overlap occurs, forexample, when an animal pest transmits a virus. In such a case, both thepest and the virus can be considered to be harmful organisms andcontrolled with appropriate control agents. However, such overlaps areunimportant for the present invention. From the perspective of thepresent invention, an adverse effect occurring in the form of nests isobserved during the cultivation of a cultivated plant in the field. Saideffect must be eliminated with appropriate control agents, wherein thequantity of control agent used is to be limited to a meaningful andeconomical extent.

The term “control” refers to a prevention of the spread or reduction inthe quantity of existing harmful organisms. In the case of theweeds/grass weeds, the term “quantity” refers, for example, to thebiomass present in the form of weeds/grass weeds. However, the term“quantity” can, especially in the case of a disease, also be understoodto mean the quantity of cultivated plants already exhibiting diseasesymptoms.

The application of a control agent to a subarea is also referred to hereas “treatment”; a “treated subarea” is a subarea on which one or morecontrol agents have been applied.

A harmful organism is controlled by application of one or more controlagents. For the individual harmful organisms, there is a multiplicity ofcontrol agents, such as, for example, herbicides (against weeds and/orgrass weeds), pesticides (against animal pests) and fungicides (againstfungi).

For example, a weed or grass weed is controlled by the application withone or more herbicides.

According to the invention, harmful organisms on a field are controlledby multiple application of a control agent at the sites at which theharmful organisms have been detected at least once and at which theformation of stable nests is expected.

The term “cultivated plant” is understood to mean a plant which iscultivated as a crop plant or ornamental plant by the intervention ofhumans in a purposeful manner.

The term “field” is understood to mean a spatially delimitable area ofthe Earth's surface, which area is utilized agriculturally by cultivatedplants being planted, supplied with nutrients and harvested on such afield.

The term “nest” is understood to mean a subarea of a field on which acertain harmful organism is observed repeatedly.

The following statements deal principally with weeds and grass weeds asharmful organisms; however, they are intended to similarly apply to allpossible harmful organisms. The invention is therefore not limited toweeds and grass weeds as harmful organisms, even though it is preferablyused for controlling weeds and/or grass weeds by means of herbicides.

The term “weed” (plural: weeds) is understood to mean plants of thespontaneous accompanying vegetation (segetal flora) in cultivated plantpopulations, grassland or garden areas, which plants are not cultivatedthere specifically and, for example, come from the seed potential in thesoil or have arrived by wind to develop. The term is not restricted toherbaceous plants in the actual sense, but also encompasses grasses,ferns, mosses or woody plants.

In the area of plant protection, the term “grass weed” (plural: grassweeds) is also frequently used in order to make clear a distinction withrespect to the herbaceous plants. In the present text, the term weed isused as an umbrella term intended to include the term grass weed, unlessreference is made to specific weeds or grass weeds.

Grass weeds and weeds in the context of the present invention aretherefore plants which accompany a desired cultivated plant during itscultivation. Since they compete with the cultivated plant for resources,they are undesired and are therefore to be controlled.

The invention is preferably used for those harmful organisms which areknown for constantly stable or recurring nests on the same subareas of afield (Nordmeyer H. 2006. Patchy weed distribution and site-specificweed control in winter cereals. Precision Agri c 7, 219-231). The nestsare generally observed beyond a vegetation period of the cultivatedplant. An example of a particularly preferred case of use is slendermeadow foxtail (Alopecurus myosuroides Huds), which has a seeddistribution close to the mother plant (Wilson B J, Brain P. 1991.Long-term stability of distribution of Alopecurus myosuroides Huds.within cereal fields. Weed Res 31, 367-373). In this case, the weednests are stable or recurring; however, new ones can also come along.Further preferred examples are Orobranche crenata Forsk in faba bean(Oveisi M, Yousefi A R, Gonzalez-Andajur J L. Spatial distribution andtemporal stability of crenate broomrape (Orobranche crenata Forsk) infaba bean (Vicia faba L.): A long-term study at two localities. CropProtection 29, 2010, 717-720), Galium aparine, V. arvensis Murr., C.album L., Polygonum aviculare L. (see overview, in Spatial and TemporalDynamics of Weed Populations. In “Precision Crop Protection—theChallenge and Use of Heterogeneity”. Eds.: Oerke, E C, Gerhards R, MenzG, Sikora R A. Springer, 2010, Heidelberg. ISBN 978-90-481-9276-2, pages17-25).

Furthermore, the invention can be applied to all diseases and animalpests which have spatially stable patterns. An example is infestation bynematodes (Campos-Herrera R., Johnson E. G., EL-Borai F. E., Stuart R.J., Graham J. H., Duncan L. W. 2011. Long-term stability ofentomopathogenic nematode spatial patterns in soil as measured bysentinel insects and real-time PCR assays, Ann Appl Biol 158: 55-68;Godefroid M., Delaville L., Marie-Luce S., Quénéhervé P. 2013. Spatialstability of a plant-feeding nematode community in relation tomacro-scale soil properties. Soil Biology & Biochemistry 57: 173-181; B.V. Ortiz, C. Perry, P. Goovaerts, G. Vellidis, and D. Sullivane.Geostatistical modeling of the spatial variability and risk areas ofsouthern root-knot nematodes in relation to soil properties. Geoderma.2010 May; 156(3-4): 243-252).

A “spatially stable pattern” refers to a repeatedly observable ormeasurable spatial distribution or arrangement of nests in a field.Furthermore, a spatially stable pattern of diseases and pests can referto i) the cause of a disease or pest infestation, ii) to the disease orthe pest infestation itself and also iii) to a characteristic feature ofa disease or of a pest infestation. For example, a pest W can transmit avirus X which leads to a disease Y having the symptom Z. It isconceivable that W, X, Y and/or Z are measurable and yield in each casea stable pattern.

In particular, said patterns can be caused by an interaction ofdevelopment cycle of the pathogen or pest with further abiotic factors.The invention can therefore also be applied to regions in the fieldwhich have a generally higher disease or pest pressure owing to theircharacter. Examples of such character factors are position or exposure,depressions, soil or field edge character (e.g. hedges).

An example that may be mentioned is Septoria leaf blotch, which arisesunder favourable conditions for infection by fungal spores of Septoriatritici. Said favourable conditions may then be present owing to arelatively high moisture or owing to a relatively low air exchange,caused by exposure, local depressions and/or soil type.

An example of a pest in which recurring patterns occur is brassica podmidge (Dasineura brassicae) in rapeseed. Owing to the low readiness tobe airborne, the distance in relation to the winter host is significantfor an infestation. A recurring pattern occurs here as a result of theposition of the field relative to that of the winter host and to that ofthe field with rapeseed cultivation in the previous year.

A further example are pathogens, the infestation pressure of which isdetermined by the degradation rate of plant remains in the soil. Stablenests can be caused here owing to local differences in the soil.

In a first step of the method according to the invention, a digitalharmful-organisms distribution map is created. Registered on this mapare subareas of the field, in which subareas the harmful organisms havebeen detected.

The term “digital” means that the maps can be processed by a machine,generally a computer system. “Processing” is understood to mean theknown methods in relation to electronic data processing (EDP).

Methods for generating digital maps on which sites at which weeds and/orgrass weeds have appeared are registered are, for example, described inthe thesis by Carina Ritter: Evaluation of weed populations under theinfluence of site-specific weed control to derive decision rules for asustainable weed management, Institute of Phytomedicine, Weed ScienceDepartment, University of Hohenheim, under the supervision of Prof. Dr.R. Gerhards, 2008 (see in particular section 1.1.5).

The methods described in GB2447681A, U.S. Pat. No. 6,199,000, US2009/0132132A1 and WO00/23937 for generating digital weeds distributionmaps can be applied here too.

During the generation of the digital harmful-organisms distribution map,the field is searched for harmful organisms. This search can be done byone (or more) individuals or by machine only. Also conceivable is amachine-assisted search by one (or more) individuals. Preferably, thesearch for harmful organisms is assisted by a position determinationsystem. This means that a person or a machine moves on or over the fieldand the current position of the person or of the machine isautomatically recorded and saved with the aid of the positiondetermination system. Appropriate position determination systems areoften subsumed under the term GPS (Global Positioning System).

If the person or the machine discovers a harmful organism at a site, itis stored on the digital map that a harmful organism has been discoveredat the site.

Besides the fact that a harmful organism has been found at a certainsite, further information can be stored on the digital map, such as, forexample, the species of the harmful organism found, the quantity, thedevelopment stage and further information.

For the automated identification of harmful organisms, the harmfulorganism can be captured as a digital image by means of a photographicdevice and then supplied to image identification methods.

The automated search of the field for harmful organisms can, forexample, be achieved using a vehicle or a pilotless flying object(drone). Also conceivable is the use of satellite pictures of the fieldfor the identification of harmful organisms.

To allow the area-specific use of various formulations, weeds/grassweeds in the weeds distribution map are preferably identified asmonocotyledons and dicotyledons or collected in groups of weeds and/orgrass weeds with respect to appropriate or effective formulations.

In the case of the generation of the harmful-organisms distribution map,it should be noted that the harmful organisms themselves are not alwaysabsolutely observed, but rather their effects on, for example, thecultivated plant. However, this is unimportant for the presentinvention. Step (A) of the method according to the invention is thus tobe understood to mean that positions are detected on the field andregistered on the digital distribution map, which positions indicate thepresence of a harmful organism. The harmful organism is thus detecteddirectly or indirectly (as a result of its effects on the environment).

The result of step (A) is a machine-readable map on which positions areregistered, at which positions harmful organisms or their effects havebeen detected.

In a following step, a digital application map is generated on the basisof the digital harmful-organisms distribution map.

The digital application map is machine-readable and specifies at whichsubareas of the field an application of one or more control agents is totake place.

The digital application map can be a so-called ON/OFF map. For example,it is conceivable that anywhere where a harmful organism is registeredon the digital harmful-organisms distribution map, it is registered onthe corresponding application map that one or more control agents are tobe applied there, whereas anywhere where no harmful organism isregistered on the harmful-organisms distribution map, it is registeredon the digital application map that no control agent is to be appliedthere.

Such an ON/OFF map is, for example, meaningful when the detection methodfor detecting harmful organisms in step (A) of the method according tothe invention is not particularly sensitive, but instead only discoversharmful organisms when they are already present in a quantity at whichan economic threshold has already been reached or even exceeded.

By contrast, if the detection method is very sensitive, the applicationof a control agent is preferably only entered in the digital applicationmap when a predefined threshold value has been reached or exceeded atthe corresponding site. To this end, it is necessary that the(approximate) quantity of the particular harmful organism present (orthe quantity of infested cultivated plant) has been recorded on thedigital harmful-organisms distribution map. On the digital applicationmap, a planned application of control agent is then registered only atthose sites at which the threshold value of harmful organism present hasbeen reached or exceeded. At all other sites, the threshold value isfallen short of, accordingly, no application of control agent isenvisaged and no planned application is registered on the applicationmap.

“Economic threshold” is a term from agriculture, forestry andhorticulture. It specifies the infestation density with pathogens,diseases or the occupation by weeds from which a control treatment iseconomically meaningful. Up to this value, the additional economicexpenditure due to a control treatment is greater than the loss ofharvest to be feared. If the infestation or the weed growth exceeds thisvalue, the control costs are at least offset by the additional yield tobe expected.

The economic threshold can vary greatly depending on the nature of apest or a disease. In the case of pests or diseases which can only becontrolled with great effort and with negative side effects for furtherproduction, the economic threshold may be very high. However, if a lowinfestation can be enough to become a propagation focal point whichthreatens to destroy the entire production, the economic threshold maybe very low.

In the prior art, there are many examples of determining economicthresholds (see, for example, Claus M. Brodersen: Informationen inSchadschwellenmodellen [Information in economic threshold models],Berichte der GIL [GIL reports], volume 7, pages 26 to 36,http://www.gil-net.de/Publikationen/7_26.pdf).

In a preferred embodiment, information concerning factors which causethe appearance of the harmful organism or favour its propagation areincluded in the creation of the digital application map.

It is conceivable that the application map contains specified quantitiesof the control agent formulation to be applied. The type of controlagent or the type of formulation can be saved on the digital applicationmap too.

The digital application map is created during the first recording of aharmful organism at a certain position and the number N of applicationsfor said harmful organism at said position is defined. The number N ofapplications is dependent on the species of the harmful organismdetected. The number of applications is at least two; preferably, it istwo, three, four or five, and it is likewise stored on the applicationmap for each subarea concerned.

In a preferred embodiment, the digital harmful-organisms distributionmap for a field is created again within the period in which the multipleapplication of a control agent is to take place as per the digitalapplication map, and the digital application map is extended by newlydiscovered nests. Subareas in which a control agent application yet tobe effected is registered in the digital application map (N>0) remain inforce, even if no more harmful organism is currently detected. Thus, ifit has been defined for a subarea on the digital application map that acontrol agent is to be applied there multiple times (N times), but thenumber of applications to be performed has in reality not yet beenreached, the information that said subareas are (still) to receive anapplication remains in force, even if no more harmful organism has beendetected at the corresponding site.

A multiple application does not necessarily mean that the sameformulation has to be used multiple times. It is conceivable to usesprays of differing formulation (“Mode of Action”) and to vary theformulation/combination of sprays from application to application.

Furthermore, the formulation can be altered accordingly in the followingyears in the event of detection of a further harmful organism on thesame subarea of a field. In particular, this can lead to subareas of afield containing one harmful organism being treated in each case withone formulation, and common subareas containing multiple harmfulorganisms being treated with a further formulation.

This may be elucidated on the basis of the following examples, in whichtwo weeds (weed 1 and weed 2) appear on the same subarea of a field.

Example 1: Weed 1 and weed 2 are sensitive to herbicide 1→Herbicide 1 isapplied.

Example 2: Weed 1 is sensitive to herbicide 1 and weed 2 is sensitive toherbicide 2 and there is no known usable herbicide which acts againstboth weed 1 and weed 2→Herbicide 1 and herbicide 2 are applied.

Example 3: Weed 1 is sensitive to herbicide 1 and weed 2 is sensitive toherbicide 2 and there is a known usable herbicide 3 which acts againstweed 1 and weed 2→It is possible to apply either herbicide 3 alone orherbicide 1 in combination with herbicide 2.

For example, the following control agents are used in controlling thegrass weed slender meadow foxtail: during the autumn use from BBCH stage11, a sulphonyl mixture consisting of the active substances mesosulfuronand iodosulforon (preferably plus safener) is used. With a change ofactive substances, propoxycarbazone or pyroxsulam and florasulam arethen used. When, in spring, the grass weed repeatedly exceeds theeconomic threshold, a treatment with, for example, the active substancesmesosulfuron and iodosulforon (plus safener) is then also carried out inspring. Besides the group of the ALS inhibitors, there is also anotheractive-substance group, that of the ACCase inhibitors with the so-calledFOPS. The nature of the active substance and the application quantitydepend on the species of the weed or grass weed, the number of plantsper m² or biomass of the weed or grass weed and the degree ofresistance.

Furthermore, it is conceivable that the digital application map containscommands for an application device for a control agent formulations.This means that the digital application map or parts thereof can beloaded into a memory of an application device, and from there thecommands are transmitted to a spray device.

An application device is understood to mean an automated device forapplying a control agent formulation to a field. Such an applicationdevice generally comprises at least one container for accommodating atleast one control agent formulation, a spray device by means of whichthe control agent formulation is dispensed on the field, and a controlunit by means of which the transport of the at least one control agentformulation from its container in the direction of the spray device iscontrolled. The digital application map is accordingly preferably savedin the memory of the control unit. Furthermore, the control unit ispreferably connected to a position determination system which determinesthe position of the application device on the field. Preferably, thecontrol unit sets in motion the application process when it isregistered on the digital application map that an application is to takeplace at one site and when the position determination system reportsthat the application device is currently situated at said site.

In a next step of the method according to the invention, the applicationof one or more control agents against the harmful organisms identifiedin step (A) takes place using the digital application map.

In one embodiment, a person (user) loads the digital application mapinto a mobile computer system, for example a mobile telephone(smartphone), which has a GPS receiver. While the user walks across thefield, the mobile computer system displays to said user, by means of agraphic image of the field, where said user is currently situated and atwhich spots said user is to manually spray (apply) one or more controlagents. Said user then manually sprays at the spots at which theapplication map contains relevant information. If the user applies acontrol agent at one spot, it is conceivable that a notification aboutthe effected application process is transmitted to the mobile computersystem via an appropriate sensor system and the effected applicationprocess is saved. It is also conceivable that the effected applicationprocess is displayed on the mobile computer system, so that the user canidentify at which spots said user has already applied. Furthermore, itis conceivable that the data recorded on the mobile computer system aretransmitted at once or at a later time to a stationary computer system(e.g. a server) and are saved therein. In any case, the effectedapplication for each subarea is recorded in the digital application mapsuch that the number N of applications (treatments) which are (still) tobe effected is decreased by one.

It is also conceivable that a person with a vehicle drives across thefield, the current position of the vehicle is recorded by means of a GPSreceiver, and commands are transmitted to a spray device on the vehicleon the basis of the digital application map when the vehicle is situatedat a site on the field at which an application of one or more controlagents is to take place as per the application map, whereupon thecorresponding application takes place automatically.

It is also conceivable that the application of one or more controlagents takes place in a fully automated manner: a machine without ahuman controller moves with GPS assistance across the field and appliesat the spots on the field at which spots a relevant application isenvisaged in the digital application map. Again, the effectedapplication is registered in the digital application map: for thetreated subareas, the number N is decreased by one.

The control of harmful organisms with appropriate chemical and/orbiological plant protectants can be supplemented by physical/mechanicalcontrol methods.

Physical removal (or else mechanical removal) is understood to meanthat, for example, the weed/grass weed as harmful organism is eithercompletely removed, or parts thereof are removed with the result thatthe weed/grass weed is no longer viable and dies. In contrast to thecontrol of the weed/grass weed with a herbicide, it being possible torefer to this as chemical control, no chemical or biological means isapplied in physical/mechanical control. Therefore, physical/mechanicalcontrol also does not exert a selection pressure on the weeds/grassweeds, but is frequently more complicated and more expensive than theapplication of herbicides.

A physical/mechanical control is also to be understood to mean, forexample, an irrigation by means of which, for example, weeds are broughtto sprout, this being desired, in order to then eliminate themspecifically. Moreover, a physical/mechanical control is also to beunderstood to mean a flame treatment of the harmful organisms.

It is, for example, conceivable to apply chemical and physical methodsin an alternating manner.

It is also conceivable to treat part of an area chemically and anotherpart physically.

Also conceivable is, however, a combined variant in one operation, forexample when the use of chemicals is limited owing to legal regulationsor there is a combination of harmful organisms in which a combinedcontrol using mechanical and chemical means has the best chances ofsuccess. The combined use of physical and chemical methods may also bemeaningful when the combination exerts a synergistic effect.

In a preferred embodiment, a physical removal of the harmful organismtakes place at the spots of the field at which spots no economicthreshold of a harmful organism has been exceeded, but at which spots aharmful organism has been detected.

The application of one or more control agents on the basis of thedigital application map takes up a certain amount of time. Said time is,for example, determined by the size of the field, the number of spots inthe field at which spots an application is to take place, the size ofsaid spots, and the quantity of control agent that an application devicecan carry (in some circumstances, the quantity of control agent that anapplication device can carry is insufficient for supplying all the spotsregistered on the application map with control agent, making itnecessary for the application device to be filled once or multipletimes, this taking up time).

“Working through the application map” is understood to mean the processin which all spots in the field for which spots it is registered on thedigital application map that one or more control agents are to beapplied have been visited by an application device and the relevantapplication has been performed.

If the application map is being worked through the first time after ithas been created, said process is referred to here as “firstapplication”.

Generally, working through the digital application map will take up fromless than one day up to 2 weeks depending on the size of the field.

The duration of the first work-through therefore occurs within a firstperiod.

It is essential to the invention that the digital application map isworked through at least a second time. The nests registered on theapplication map are thus sprayed multiple times (e.g. 2 times, 3 times,4 times or 5 times) with a control agent.

Therefore, step (C) of the method according to the invention is followedby a step (D) in which spraying is carried out again to the same siteson the application map within a second period (second work-through ofthe application map).

It is conceivable that the same application map is worked through athird time within a third period.

It is conceivable that the same application map is worked through afourth time within a fourth period.

A further repeated work-through is conceivable, but any furtherwork-through taking place after the third work-through is less likely.

Steps (C) and (D) can therefore also be subsumed under the point:multiple use of the digital application map generated in step (B) suchthat one or more control agents are applied multiple times (N times) atthe subareas of the field at which subareas an economic threshold of oneor more harmful organisms has been exceeded (even if no more harmfulorganism is detected at the time of application).

As described above, the application map can be extended at any time byincorporating newly detected nests.

Between the first work-through of the application map within the firstperiod (step (C)) and the second work-through of the application mapwithin the second period (step (D)) is a period in which there is noapplication of a control agent. Said period is at least one day,preferably at least one week, even more preferably at least one month.If the application map is worked through a third time in a third period,there is again, between the second period and the third period, a periodof at least one day, preferably at least one week, even more preferablyat least one month, in which period there is no application.

A similar consideration applies to any further work-through of theapplication map.

The interval between two treatments of a subarea is substantiallydetermined by when a renewed appearance of harmful organisms isexpected. A subarea is thus preferably only treated a further time whena renewed appearance of harmful organisms is expected, particularlypreferably before a renewed infestation of the subarea with the harmfulorganisms spreads further to other subareas.

The multiple (at least twice) work-through of the application map ispreferably done over the current vegetation year and/or followingvegetation year, in each case within the time period of thepre-sprouting phase to the end of the vegetation period of thecultivated plant which is cultivated on the field.

“Pre-sprouting phase” is considered here to be the time period from thefirst day after harvest of the previous crop up to the last day beforethe sprouting of the crop.

In one embodiment of the present invention, the period between twoapplications corresponds to the duration of a vegetation period of thecultivated plant that is cultivated (plus/minus 1 day to 8 weeks).

Preferably, an extended digital harmful-organisms distribution map iscreated each year on the agriculturally used field, firstly in order tocheck the population of harmful organisms, and secondly in order toadapt the digital application map by optionally incorporating newlyadded sites at which an economic threshold has been exceeded.

In particular with the effective control of, for example, weeds/grassweeds, the invention leads to a lower development of resistances:

The resistance pressure of a field with subarea-specific application isaltogether lower than on an area without subarea-specific application,since precisely only part of the area of the field is exposed to theselection pressure.

The application of the same quantity or concentration of a herbicide toa subarea as also in the case of non-subarea-specific application avoidsso-called multigenic resistances, which otherwise build upquantitatively with repeated spraying at low doses.

This is in line with ‘good agricultural practice’.

Owing to repeated use of the application map, the survival of singleindividuals of weeds/grass weeds becomes less likely on the identifiedpatches of the weed identification map. An annual creation of the mapchecks this situation and thus counteracts a resistance on non-treatedsubareas.

The use of various herbicides increases the success of treatment andthus reduces the development of resistances to a certain spray.

Preferred embodiments of the present invention are in particular:

Embodiment 1: A method for controlling weeds and/or grass weeds on afield on which cultivated plants are cultivated, comprising thefollowing steps: (A) generating a digital weeds distribution map onwhich sites on the field are registered, at which sites the weeds and/orthe grass weeds have been detected; (B) generating a digital applicationmap on the basis of the digital weeds distribution map, it beingregistered on the digital application map those sites on the field atwhich sites an economic threshold of one or more weeds and/or grassweeds has been exceeded and at which sites one or more herbicidesagainst the weeds and/or grass weeds are to be applied; (C) a firstapplication of one or more herbicides against the weeds and/or grassweeds using the digital application map from step (B); (D) at least afurther application of one or more herbicides against the weeds and/orgrass weeds using the digital application map from step (B).

Embodiment 2: The method according to embodiment 1, wherein the numberof applications of one or more herbicides on the basis of the digitalapplication map from step (B) is two, three or four.

Embodiment 3: The method according to either of embodiments 1 and 2,wherein a digital weeds distribution map is generated again as per step(A) after an application of one or more herbicides and an addition ismade in step (B) in the existing digital application map to thoseregions in which economic thresholds of one or more weeds and/or grassweeds have been exceeded in the new digital weeds distribution map.

Embodiment 4: The method according to any of embodiments 1, 2 and 3,wherein a mechanical removal of weeds and/or grass weeds or partsthereof takes place at least in part of the regions of the field inwhich regions weeds and/or grass weeds have been detected, but in whichregions no economic threshold has been exceeded.

Embodiment 5: The method according to any of embodiments 1 to 4,wherein, in the digital application map, a number for the multipleapplications of one or more herbicides is registered for each site inwhich an economic threshold of a weed/grass weed has been reached orexceeded, the number being reduced by one with each effected applicationuntil all planned applications have been effected and the sites areremoved from the application map.

Embodiment 6: A system for controlling weeds and/or grass weeds,comprising: (a) a digital weeds distribution map on which sites on afield, on which cultivated plants are cultivated are registered, atwhich sites weeds and/or the grass weeds, have been detected; (b) adigital application map on which those sites on the field, at whichsites an economic threshold has been exceeded for the detected weedsand/or grass weeds, are registered; (c) a position determination system;(d) an application device comprising

at least one container for accommodating at least one herbicideformulation,

a spray device for applying the herbicide formulation, and

a control unit having a memory for reading in the digital applicationmap, a connection to the position determination system, and means forcontrolling the spray device.

Embodiment 7: The system according to embodiment 6, wherein the controlunit starts the application of at least one herbicide formulation bymeans of the spray device when the position determination system signalsthat the application device is situated at a site at which theapplication of the at least one herbicide formulation is envisagedaccording to the digital application map.

Embodiment 8: The system according to either of embodiments 6 and 7,wherein, in the digital application map, a number for the multipleapplications of one or more herbicides is registered for each site inwhich an economic threshold of a weed/grass weed has been reached orexceeded, the number specifying how many applications must still beeffected at the site.

Embodiment 9: Use of a digital application map on which sites on a fieldare registered, at which sites an economic threshold of one or moreweeds and/or grass weeds has been exceeded, for the multiple applicationof one or more herbicides against the weeds and/or grass weeds, whereina plurality of applications is inputted in the application map for eachsite for which an economic threshold of a weed/grass weed has beenexceeded, the number being reduced by one with each effectedapplication.

The invention will be more particularly elucidated below on the basis ofan example.

The FIGURE shows different representations of a field at various pointsin time t₁ to t₆. The representations of the field are depicted as arectangle. The top row labelled with U1 is a weed distribution map forthe weed U1. The middle row labelled with U2 is a weed distribution mapfor the weed U2. The bottom row labelled with A is an application mapfor two different herbicides H1 and H2.

Time is divided into six snapshots t₁ to t₆. In this connection, timeadvances column by column from left to right.

Therefore, the first column depicts the field at a first point in time,the second column depicts the field at a later second point in time, andso on. The periods which lie between two columns can, for example, bethe duration of a vegetation period (generally one year) of thecultivated plant which is cultivated on the field. The period can alsobe the vegetation period of a weed/grass weed. In general, theapplication of one or more herbicides has taken place in the time periodlying between two successive columns—this is depicted in the bottom rowA—unless no weeds were detected over multiple time segments (lastcolumn).

In the top row, it is depicted where in the field at the points in timet₁ to t₆ the weed U1 has been detected.

Fields U1(t ₁), U1(t ₂), U1(t ₆), U1(t ₄), U1(t ₅) and U1(t ₆) thereforerepresent weeds distribution maps with regard to weed U1. Analogously,fields U2(t ₁), U2(t ₂), U2(t ₃), U2(t ₄), U2(t ₅) and U2(t ₆) representweeds distribution maps with regard to weed U2. The distributions ofweeds 1 and 2 could also have been pooled in a single distribution map,but they are depicted here separately.

At point in time t₁, a weed U1 was identified in the field; weed U1 waspresent in the form of a circular region (=subarea) (see U1(t ₁)).

At the same point in time t₁, there was no weed U2 in the field (seeU2(t ₁)).

An application map A(t₁) was created from weeds distribution maps U1(t₁) and U2(t ₁). Since only weed U1 was detected on the field,application map A(t₁) also contains only information and instructionswith regard to weed U1. In application map A(t₁), a circular region ismarked with hatching, in which region weed U1 was detected in U1(t ₁).In said region, it is intended that herbicide H1 be applied. The numeral3 above the hatched region indicates that this subarea is to be treateda total of three times (N=3) with herbicide H1.

At a later point in time after the application of herbicide H1, it canbe seen in U1(t ₂) that weed U1 is clearly no longer to be detected inthe prior circular region; the application of herbicide H1 was clearlysuccessful. However, a crescent region next to the previous circularregion has evolved instead, in which crescent region weed U1 wasdetected. Thus, weed U1 has shifted right in the field.

In addition, a weed U2 has appeared (see U2(t ₂)). These findings yieldapplication map A(t). First of all, A(t₂) shows that herbicide H1 is tobe further applied in the circular region in which weed U1 was detectedin U1(t ₁), even though it was no longer detected in U1(t). This isprecisely the core of the present invention: application map A(t₁) isused/worked through multiple times. The numeral 2 above the hatchedregion indicates that this subarea is to be treated twice more (N=3−1=2)with herbicide H1.

Application map A(t₁) has been extended to A(t₂) on the basis of thefindings in U1(t ₂) and U2(t ₂). Since a crescent region of weed U1 hasnow been detected in U1(t ₂), the hatched region was extendedaccordingly in A(t). The numeral 3 above the extended hatched regionindicates that said extended region is to be treated a total of threetimes (N=3) with herbicide H1.

In addition, A(t₂) indicates that herbicide H2 is to be applied in theregion (wavy region) in which weed U2 was detected in U2(t ₂). Thenumber 4 below the wavy region indicates that this subarea is to betreated a total of four times (N=4) with herbicide H2.

U1(t ₃) shows that the region containing weed U1 has shifted furtherright. In U2(t ₃), weed U2 has completely disappeared. A(t₃) representsthe application map associated with U1(t ₃) and U2(t ₃). In the circularregion of A(t₁), herbicide H1 is also to be further applied as perA(t₃), specifically once more (N=1). In the crescent region too whichwas added to the circular region in A(t₂), herbicide H1 is to be furtherapplied, specifically twice more (N=2). In addition, herbicide H1 is tobe applied in the region which newly appeared in U1(t ₃), specifically atotal of three times (N=3).

As per A(t₆), herbicide H2 is, too, to be applied once again,specifically in the same region as in A(t). No new regions with weed U2were added in U2(t ₃).

U1(t ₄) shows that no more weed U1 was detected on the field after theapplication as per A(t₆). U2(t ₄) shows that no more weed U2 wasdetected on the field after the application as per A(t₆). Nevertheless,herbicides H1 and H2 are applied as per A(t₄). In the circular regionfrom A(t₁), no more herbicide H1 is applied for the first time in A(t₄)(N=0). In said region, herbicide H1 was applied three times—this numberof applications is sufficient for permanently eliminating the nest.

In the crescent regions which were added to the circular region in A(t₂)and A(t₃), application is to be carried out once again; once more (N=1)in the case of the crescent region that appeared first (see U1(t ₂)),twice more (N=2) in the case of the crescent region that appearedthereafter (see U1(t ₃)).

The region from U2(t ₂) is to be treated with herbicide H2 twice more(N=2) in A(t₄).

In U1(t ₅) and U2(t ₅), no more weed was further detected. Nevertheless,herbicide H1 and herbicide H2 are further to be applied as per A(t₅): alast time (N=1) in the region of U1(t ₃) with herbicide H1 and a last(N=1) time in the region of U2(t ₂) with herbicide H2.

U1(t ₆) and U2(t ₃) indicate that no more weed was further detected. Asper A(t₆), an application of a herbicide is not necessary.

It should be additionally noted that this example did not explicitlymention the economic thresholds of weed U1 and weed U2. In this example,it could be assumed, for example, that whenever weed U1 or weed U2 wasdetected in the field, the economic thresholds had been exceeded.

What is claimed is:
 1. A method for controlling harmful organisms on afield on which cultivated plants are cultivated, which method comprisesthe following steps: (A) generating a digital harmful-organismsdistribution map on which subareas on the field are registered, in whichsubareas the harmful organisms have been detected directly orindirectly; (B) generating a digital application map on the basis of thedigital harmful-organisms distribution map, it being registered on thedigital application map those subareas of the field on which subareasone or more control agents against the harmful organisms are to beapplied, it being registered for each of said subareas a number N oftreatments with one or more control agents, wherein N is greater than 1;(C) applying one or more control agents against the harmful organisms asper the digital application map from step (B), the number N for thetreated subareas being reduced by 1; and (D) repeating step (C) for eachsubarea until N has reached for the value zero, wherein there isincorporation into the digital application map in step (B) of thosesubareas of the field in which subareas there has been detection in step(A) of nests with harmful organisms that have survived after anapplication of one or more control agents.
 2. The method according toclaim 1, wherein those subareas of the field in which subareas harmfulorganisms have been detected directly or indirectly in step (A) and inwhich subareas an economic threshold has been reached or exceeded areincorporated into the digital application map.
 3. The method accordingto claim 1, wherein the harmful organisms are weeds and/or grass weedsand the one or more control agents are one or more herbicides.
 4. Themethod according to claim 1, wherein the harmful organisms are animalpests, and in which the one or more control agent are pesticides.
 5. Themethod according to claim 1, wherein the number N in the generation ofthe digital application map is set to two, three or four.
 6. The methodaccording to claim 1, wherein the control of the harmful organisms witha control agent is accompanied by a physical control or in that aphysical control of the harmful organisms takes place at least in partof regions of the field in which regions harmful organisms have beendetected, but in which regions no economic threshold has been exceeded.7. A method for controlling harmful organisms on a field on whichcultivated plants are cultivated, which method comprises the followingsteps: (A) generating a digital harmful-organisms distribution map onwhich subareas on the field are registered, in which subareas theharmful organisms have been detected directly or indirectly; (B)generating a digital application map on the basis of the digitalharmful-organisms distribution map, it being registered on the digitalapplication map those subareas of the field on which subareas one ormore control agents against the harmful organisms are to be applied, itbeing registered for each of said subareas a number N of treatments withone or more control agents, wherein N is greater than 1; (C) applyingone or more control agents against the harmful organisms as per thedigital application map from step (B), the number N for the treatedsubareas being reduced by 1; and (D) repeating step (C) for each subareauntil N has reached for the value zero, wherein a new digitalharmful-organisms distribution map is generated again as per step (A)after an effected application of one or more control agents to thesubareas concerned, and additions are made in step (B) in the digitalapplication map to those regions in which harmful organisms have beendetected in the new digital harmful-organisms distribution map, thesubareas in which N has not yet reached the value zero remaining inforce and subareas in which N has reached the value zero being deleted.8. The method according to claim 7, wherein those subareas of the fieldin which subareas harmful organisms have been detected directly orindirectly in step (A) and in which subareas an economic threshold hasbeen reached or exceeded are incorporated into the digital applicationmap.
 9. The method according to claim 7, wherein the harmful organismsare weeds and/or grass weeds and the one or more control agents are oneor more herbicides.
 10. The method according to claim 7, wherein theharmful organisms are animal pests, and in which the one or more controlagent are pesticides.
 11. The method according to claim 7, wherein thenumber N in the generation of the digital application map is set to two,three or four.
 12. The method according to claim 7, wherein the controlof the harmful organisms with a control agent is accompanied by aphysical control or in that a physical control of the harmful organismstakes place at least in part of regions of the field in which regionsharmful organisms have been detected, but in which regions no economicthreshold has been exceeded.
 13. A system for controlling harmfulorganisms, the system comprising: a digital application map configuredfor display by a display device, the digital application map beingdescriptive of on which those subareas of a field which are to betreated with one or more control agents for the harmful organisms areregistered; a position determination system; and an application devicecomprising: at least one container for accommodating at least onecontrol agent against the harmful organisms; a spray device for applyingthe at least one control agent; a control unit comprising a memory forreading in the digital application map; and means for communicating withthe position determination system and means for controlling the spraydevice, wherein a number N is registered on the digital application mapfor each of the subareas, which number specifies how many times atreatment of the subarea with the control agent is to take place,wherein N is greater than 1, wherein the control unit is equipped insuch a way that the number N is reduced by one after a treatment hastaken place, and wherein there is incorporation into the digitalapplication map subareas of the field in which there has been detectionof nests with harmful organisms that have survived after an applicationof one or more control agents.
 14. The system according to claim 13,wherein those subareas of the field in which subareas harmful organismshave been detected directly or indirectly in step (A) and in whichsubareas an economic threshold has been reached or exceeded areincorporated into the digital application map.
 15. The system accordingto claim 13, wherein the harmful organisms are weeds and/or grass weedsand the one or more control agents are one or more herbicides.
 16. Thesystem according to claim 13, wherein the harmful organisms are animalpests, and in which the one or more control agent are pesticides. 17.The system according to claim 13, wherein the number N in the generationof the digital application map is set to two, three or four.
 18. Thesystem according to claim 13, wherein the control of the harmfulorganisms with a control agent is accompanied by a physical control orin that a physical control of the harmful organisms takes place at leastin part of regions of the field in which regions harmful organisms havebeen detected, but in which regions no economic threshold has beenexceeded.
 19. A digital application map configured for display by adisplay device, wherein the digital application map is generatedaccording to the method of claim
 1. 20. A digital application mapconfigured for display by a display device, wherein the digitalapplication map is generated according to the method of claim 7.